In SX Microcontrollers, SX/B Compiler and SX-Key Tool, JonnyMac wrote:

If you need to test a specific bit in a value for 0 or 1 you can do it like this:

[code]CHECK_BIT       FUNC    1, 3, 3, Byte, Word, Byte[/code]
[code]' Use: result = CHECK_BIT value, bitpos

FUNC CHECK_BIT
  testVal       VAR     __WPARAM12
  bitPos        VAR     __PARAM3
  mask          VAR     __WPARAM45
  result        VAR     __PARAM1

  ASM
    CJA   bitPos, #15, @CB_False

    MOV   mask_LSB, #1
    CLR   mask_MSB
    TEST  bitPos
    JZ    @Do_Check

Shift_Mask:
    CLC
    RL    mask_LSB
    RL    mask_MSB
    DJNZ  bitPos, @Shift_Mask

Do_Check:
    AND   mask_LSB, testVal_LSB
    AND   mask_MSB, testVal_MSB

    MOV   result, #1
    MOV   W, mask_LSB
    OR    W, mask_MSB
    SNZ

CB_False:
    CLR  result

CB_Exit:
  ENDASM
  ENDFUNC[/code]

---------- End of Message ----------


You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=371089#m371145

Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com

The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2009 (http://www.dotNetBB.com)